Curable toner compositions and processes

Abstract

Processes for producing emulsion aggregation toners are provided. In embodiments, methods of the present disclosure may be utilized to produce toners suitable for low melt applications, including use in flexible packaging applications, where low pile height is desired for low cost and flexibility. In embodiments, the EA toners may be prepared by optimizing the particle size of the emulsion, the choice of and amount of aggregating agent utilized, and the solids content of the emulsion.

1. A process comprising:
 contacting an emulsion comprising at least one amorphous polyester resin in combination with at least one crystalline polyester resin with an optional wax and an optional colorant, the emulsion having a particle size of from about 50 nm to about 200 nm and a solids content of from about 10% to about 50% by weight; 
 aggregating the particles by contacting the particles with from about 0.1 parts per hundred to about 2 parts per hundred of an aggregating agent selected from the group consisting of aluminum sulfate, polyaluminum chloride, polyaluminum bromide, polyaluminum fluoride, polyaluminum iodide, polyaluminum silicate, polyaluminum sulfosilicate, aluminum chloride, aluminum nitrite, aluminum sulfate, potassium aluminum sulfate, and combinations thereof to form aggregated particles; 
 contacting the aggregated particles with at least one unsaturated polymeric resin in combination with a photoinitiator to form a shell over the aggregated particles; 
 coalescing the aggregated particles to form toner particles; and 
 recovering the toner particles. 
 
     
     
       2. The process according to  claim 1 , wherein the polymeric resin comprises an amorphous polyester resin. 
     
     
       3. The process according to  claim 1 , wherein the polymeric resin comprises a crystalline polyester having a number average molecular weight of from about 1,000 to about 50,000, a weight average molecular weight of from about 2,000 to about 100,000, and a molecular weight distribution (Mw/Mn) of from about 2 to about 6. 
     
     
       4. The process according to  claim 1 , wherein the wherein the polymeric resin comprises an amorphous polyester resin of the formula: 
       
         
           
           
               
               
           
         
       
       wherein m may be from about 5 to about 1000, in combination with a crystalline polyester resin of the formula: 
       
         
           
           
               
               
           
         
       
       wherein b is from about 5 to about 2000 and d is from about 5 to about 2000. 
     
     
       5. The process according to  claim 1 , wherein the photoinitiator is selected from the group consisting of hydroxycyclohexylphenyl ketones, other ketones, benzoins, benzoin alkyl ethers, benzophenones, trimethylbenzoylphenylphosphine oxides, azo compounds, anthraquinones, substituted anthraquinones, other substituted or unsubstituted polynuclear quinines, acetophenones, thioxanthones, ketals, acylphosphines, and mixtures thereof. 
     
     
       6. The process according to  claim 1 , wherein the photoinitiator is selected from the group consisting of alpha-amino ketone, 4-(2-hydroxyethoxy)phenyl-(2-hydroxy-2-propyl) ketone, 2,4,6-trimethylbenzophenone, 4-methylbenzophenone, 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide, phenylbis(2,4,6-trimethylvbenzyoyl) phosphine oxide, alkyl substituted or halo substituted anthraquinones, 2-hydroxy-2-methyl-1-phenyl-propan-1-one, 2-isopropyl-9H-thioxanthen-9-one, 2-Hydrox-4′-hydroxyethoxy-2-methylpropiophenone, 1-hydroxycyclohexylphenyl ketone, ethyl-2,4,6-trimethylbenzoylphenylphosphinate, and mixtures thereof. 
     
     
       7. The process according to  claim 1 , wherein the polymeric resin is present in an amount of from about 65 percent by weight to about 95 percent by weight of the toner particles and the photoinitiator is present in an amount of from about 0.5 percent by weight to about 15 percent by weight of the toner particles. 
     
     
       8. The process according to  claim 1 , wherein the toner particles possess a Number Average Geometric Standard Deviation or Volume Average Geometric Standard Deviation of from about 1.18 to about 1.30. 
     
     
       9. The process according to  claim 1 , wherein the toner particles have a gloss of from about 20 ggu to about 100 ggu. 
     
     
       10. The process according to  claim 1 , wherein the aggregating agent comprises aluminum sulfate. 
     
     
       11. A process comprising:
 contacting an emulsion comprising at least one amorphous polyester resin in combination with at least one crystalline polyester resin with an optional wax and an optional colorant, the emulsion having a particle size of from about 50 nm to about 200 nm and a solids content of from about 10% to about 50% by weight; 
 aggregating the particles by contacting the particles with from about 0.1 parts per hundred to about 2 parts per hundred of an aggregating agent selected from the group consisting of aluminum sulfate, polyaluminum chloride, polyaluminum bromide, polyaluminum fluoride, polyaluminum iodide, polyaluminum silicate, polyaluminum sulfosilicate, aluminum chloride, aluminum nitrite, aluminum sulfate, potassium aluminum sulfate, and combinations thereof to form aggregated particles; 
 contacting the aggregated particles with at least one unsaturated polymeric resin in combination with a photoinitiator to form a shell over the aggregated particles; 
 coalescing the aggregated particles to form toner particles; 
 recovering the toner particles; 
 applying the toner particles to a substrate; and 
 fusing the toner particles to the substrate by non-contact fusing to form an image on the substrate, 
 wherein the toner has a gloss of from about 20 ggu to about 100 ggu and the image on the substrate has a toner pile height of from about 1 micron to about 6 microns. 
 
     
     
       12. The process according to  claim 11 , wherein the polymeric resin comprises an amorphous polyester resin. 
     
     
       13. The process according to  claim 11 , wherein the polymeric resin comprises a crystalline polyester having a number average molecular weight of from about 1,000 to about 50,000, a weight average molecular weight of from about 2,000 to about 100,000, and a molecular weight distribution (Mw/Mn) of from about 2 to about 6. 
     
     
       14. The process according to  claim 11 , wherein the wherein the polymeric resin comprises an amorphous polyester resin of the formula: 
       
         
           
           
               
               
           
         
       
       wherein m may be from about 5 to about 1000, in combination with a crystalline polyester resin of the formula: 
       
         
           
           
               
               
           
         
       
       wherein b is from about 5 to about 2000 and d is from about 5 to about 2000. 
     
     
       15. The process according to  claim 11 , wherein the photoinitiator is selected from the group consisting of hydroxycyclohexylphenyl ketones, other ketones, benzoins, benzoin alkyl ethers, benzophenones, trimethylbenzoylphenylphosphine oxides, azo compounds, anthraquinones, substituted anthraquinones, other substituted or unsubstituted polynuclear quinines, acetophenones, thioxanthones, ketals, acylphosphines, and mixtures thereof. 
     
     
       16. The process according to  claim 11 , wherein the photoinitiator is selected from the group consisting of alpha-amino ketone, 4-(2-hydroxyethoxy)phenyl-(2-hydroxy-2-propyl) ketone, 2,4,6-trimethylbenzophenone, 4-methylbenzophenone, 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide, phenylbis(2,4,6-trimethylvbenzyoyl) phosphine oxide, alkyl substituted or halo substituted anthraquinones, 2-hydroxy-2-methyl-1-phenyl-propan-1-one, 2-isopropyl-9H-thioxanthen-9-one, 2-Hydrox-4′-hydroxyethoxy-2-methylpropiophenone, 1-hydroxycyclohexylphenyl ketone, ethyl-2,4,6-trimethylbenzoylphenylphosphinate, and mixtures thereof. 
     
     
       17. The process according to  claim 11 , wherein the polymeric resin is present in an amount of from about 65 percent by weight to about 95 percent by weight of the toner particles and the photoinitiator is present in an amount of from about 0.5 percent by weight to about 15 percent by weight of the toner particles. 
     
     
       18. The process according to  claim 11 , wherein the toner particles possess a Number Average Geometric Standard Deviation or Volume Average Geometric Standard Deviation of from about 1.18 to about 1.30. 
     
     
       19. The process according to  claim 11 , wherein the aggregating agent comprises aluminum sulfate. 
     
     
       20. The process according to  claim 11 , wherein the image on the substrate has a toner pile height of from about 2 microns to about 4 microns.